INTRODUCTION: Rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (ACPA) are used in the diagnosis and prognostication of rheumatoid arthritis (RA). We wanted to determine the specific contributions of RF and ACPA to the biological nature of RA and whether they act synergistically. METHODS: We identified 731 patients from our prospective multi-ethnic RA cohort and categorised them into four groups: ACPA-positive, RF-positive, doubly positive and doubly negative. We compared the demographics, Disease Activity Score-28, Health Assessment Questionnaire score, quality of life using Short Form 36 and the use of prednisolone and disease-modifying antirheumatic drugs (DMARDs) of these patient groups. RESULTS: Four hundred and ninety-one patients (67.2%) were ACPA+RF+, 54 (7.4%) were ACPA+RF-, 82 (11.2%) were ACPA-RF+ and 104 (14.2%) were ACPA-RF-. Mean disease duration before the study entry was not different in the four groups. Patients with older age of onset were less likely to be positive for RF and ACPA. Fewer ACPA+RF+ patients were in remission compared to those in the other groups ( P < 0.05). Erythrocyte sedimentation rate (ESR) was higher at study entry in the ACPA+RF+ group (40.4 mm/h vs. 30.6-30.9 mm/h, P < 0.05). Prednisolone and number of DMARDs used were higher in the ACPA+RF+ group compared to the doubly negative group. There were no differences in the functional status and quality of life. CONCLUSIONS RA patients who were positive for both ACPA and RF had lower remission rate, higher baseline ESR and required more corticosteroid and DMARD treatment compared to those who were singly positive or doubly negative. Being doubly positive confers a worse outcome to RA patients.
Humans ; Arthritis, Rheumatoid/diagnosis* ; Male ; Female ; Middle Aged ; Rheumatoid Factor/blood* ; Anti-Citrullinated Protein Antibodies/blood* ; Adult ; Quality of Life ; Prospective Studies ; Antirheumatic Agents/therapeutic use* ; Aged ; Peptides, Cyclic/immunology* ; Prednisolone/therapeutic use* ; Surveys and Questionnaires ; Severity of Illness Index ; Prognosis

OBJECTIVE: To explore, identify, and develop novel blood-based indicators using machine learning algorithms for accurate preoperative assessment and effective prediction of postoperative complication risks in patients with rheumatoid arthritis (RA) undergoing total knee arthroplasty (TKA). METHODS: A retrospective cohort study was conducted including RA patients who underwent unilateral TKA between January 2019 and December 2024. Inpatient and 30-day postoperative outpatient follow-up data were collected. Six machine learning algorithms, including decision tree, random forest, logistic regression, support vector machine, extreme gradient boosting, and light gradient boosting machine, were used to construct predictive models. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC), F1-score, accuracy, precision, and recall. SHapley Additive exPlanations (SHAP) values were employed to interpret and rank the importance of individual variables. RESULTS: According to the inclusion criteria, a total of 1 548 patients were enrolled. Ultimately, 18 preoperative indicators were identified as effective predictive features, and 8 postoperative complications were defined as prediction labels for inclusion in the study. Within 30 days after surgery, 453 patients (29.2%) developed one or more complications. Considering overall accuracy, precision, recall, and F1-score, the random forest model [AUC=0.930, 95% CI (0.910, 0.950)] and the extreme gradient boosting model [AUC=0.909, 95% CI (0.880, 0.938)] demonstrated the best predictive performance. SHAP analysis revealed that anti-cyclic citrullinated peptide antibody, C-reactive protein, rheumatoid factor, interleukin-6, body mass index, age, and smoking status made significant contributions to the overall prediction of postoperative complications. CONCLUSION Machine learning-based models enable accurate prediction of postoperative complication risks among RA patients undergoing TKA. Inflammatory and immune-related blood biomarkers, such as anti-cyclic citrullinated peptide antibody, C-reactive protein, and rheumatoid factor, interleukin-6, play key predictive roles, highlighting their potential value in perioperative risk stratification and individualized management.
Humans ; Arthroplasty, Replacement, Knee/adverse effects* ; Arthritis, Rheumatoid/blood* ; Machine Learning ; Postoperative Complications/blood* ; Female ; Male ; Retrospective Studies ; Middle Aged ; Aged ; Risk Factors ; Preoperative Period ; C-Reactive Protein/analysis* ; Risk Assessment

Objective To explore the expression of coagulation indexes in rheumatoid arthritis (RA) and dry syndrome (pSS) and their relationships with inflammation and immune function. Methods A total of 61 patients with RA who were hospitalized in the Department of Rheumatology of Anhui Provincial Hospital of Traditional Chinese Medicine from March 12 to September 9, 2024 were selected as the RA group. And 61 patients with pSS who were hospitalized in the Department of Rheumatology of the same hospital September 4, 2023, to August 17, 2024, were selected as the pSS group. 61 healthy individuals who underwent routine medical checkups at the Physical Examination Center of Anhui Provincial Hospital of Traditional Chinese Medicine during the same period were included as the control group. Baseline clinical indexes before treatment were collected from patients in each group, including prothrombin time(PT), international normalized ratio(INR), thrombia time(TT), fibrinogen(FBG), activated partial thromboplastin time(APTT), fibrin (ogen) degradation products(FDP) and D-Dimer(D-D). Results The expression levels of PT, FBG, TT, FDP, and D-D in the RA group, the pSS group, and the normal group were significantly different. The expression levels of PT, FBG, FDP, and D-D in the RA group were all higher than those in the pSS group and the control group, respectively. And the expression level of TT in the pSS group was lower than that in control group. ROC curve analysis showed that the AUC of PT was 0.638, the AUC of FBG was 0.899, the AUC of FDP was 0.866, and the AUC of D-D was 0.919 in the RA group compared with the normal group. And the AUC of coagulation indexes for joint diagnosis of RA was higher than that of the indexes detected individually. pSS group had an AUC of PT of 0.618 compared with that of the normal group. The AUC of TT was 0.645, and the AUC of coagulation indexes for the joint diagnosis of pSS was higher than the AUC of each index detected separately. Association rule analysis showed that elevated D-D in RA patients had a significant correlation with elevated hs-CRP, CCP and RF, and elevated FBG had a significant correlation with elevated hs-CRP, ESR, RF and CCP. Elevated D-D in pSS patients had a correlation with elevated hs-CRP and anti-SSA, and elevated INR has correlation with elevated hs-CRP, anti-SSA and anti-SSB. Correlation analysis showed that PT, INR, FBG, FDP, and D-D were positively correlated with CRP and ESR, and TT was negatively correlated with CRP and ESR in the RA group. FBG, FDP, and D-D were positively correlated with CRP and ESR in the pSS group. Moreover, coagulation indexes were positively correlated with immune indexes in RA group and pSS group which were all significant. The results of multiple linear regression analysis showed that FBG was a positive correlate of hs-CRP and ESR in RA patients. For PSS patients, FBG and FDP were positive correlates of hs-CRP. APTT and FBG were positive correlates of ESR. Conclusion Compared with pSS, coagulation indexes (especially PT, FBG, FDP and D-D) are more informative for the early diagnosis of RA and the judgment of the degree of the disease, and can be used as an important predictor for the confirmation of the diagnosis of RA.
Humans ; Female ; Male ; Arthritis, Rheumatoid/diagnosis* ; Middle Aged ; Fibrin Fibrinogen Degradation Products/analysis* ; Blood Coagulation ; Adult ; Fibrinogen/metabolism* ; Partial Thromboplastin Time ; Prothrombin Time ; Aged ; Inflammation/immunology* ; ROC Curve

OBJECTIVE: To investigate the serum level of lumican (LUM) and its clinical correlation with disease and immune activities in patients with rheumatoid arthritis (RA). METHODS: The serum LUM levels in both RA patients and health controls (HCs) were detected by enzyme-linked immunosorbent assay (ELISA). The clinical and laboratory data of the patients were collected. The LUM levels in the patients with different clinical features were analyzed. The correlation between the clinical data, laboratory parameters, and serum LUM levels were also analyzed. Independent samples t test, Spearman correlation were used for statistical analysis. Analysis of variance and Kruskal-Wallis test, the least significant difference (LSD)-t test and Bonferroni correction were used for statistical analysis. The Pearson Chi-square test was used for comparison of the rates between the groups. Statistical significance was set at P < 0.05. RESULTS: The levels of LUM were elevated in the RA patients than in the HCs (P < 0.000 1). Serum LUM levels were correlated with the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), immunoglobulin A (IgA), titers of platelet (PLT) and 28-joint disease activity score (DAS28, all P < 0.05). Next, we compared the serum LUM levels in the RA patients with different characteristics, and no difference was found in serum LUM levels between early-RA and RA, the same to RA with different gender (P>0.05). The levels of serum LUM were elevated in the RF positive patients (P < 0.000 1), and in the RF and anti-CCP positive patients (P < 0.05) than in the RA patients with negative RF whether the anti-CCP was positive. In addition, no differences were found between the RA patients with negative RF whether the anti-CCP was positive (P>0.05). All the levels of serum LUM were elevated in the RA patients with different CRP or ESR than in the HCs (P < 0.05), and the serum LUM levels in the RA patients with elevated ESR and CRP were significantly elevated in those with normal ESR and CRP (P < 0.05). Additionally, the results demonstrated that serum LUM levels were positively associated with RA disease activity, and they were declined in RA sustained remission than those in middle or high disease activity (P < 0.05). Furthermore, no difference was found between the RA patients in remission and HCs (P>0.05). No differences were found in the RA patients with and without complications including interstitial pneumonia disease, Sjögren's syndrome, thyroid gland diseases and osteoporosis (P>0.05). The LUM positivity rates were significantly elevated in the RF positive patients than the RF negative patients in RA (P < 0.05). CONCLUSION LUM, a cyclocitrullinated protein, might be a promising biomarker which could reflect both disease activity and immune activity in RA.
Humans ; Arthritis, Rheumatoid/immunology* ; Lumican/blood* ; C-Reactive Protein/metabolism* ; Female ; Male ; Rheumatoid Factor/blood* ; Middle Aged ; Adult ; Chondroitin Sulfate Proteoglycans/blood* ; Blood Sedimentation ; Keratan Sulfate/blood* ; Enzyme-Linked Immunosorbent Assay ; Aged

OBJECTIVES: To analyze the molecular mechanism of Xixian Pills for treatment of rheumatoid arthritis (RA). METHODS: Forty-eight rats were randomized into 6 groups (n=8), including a normal control group, a collagen-induced arthritis (CIA) model group, 3 Xixian Pills treatment (200, 400 and 800 mg/kg) groups, and a Tripterygium glycosides tablet (TGT) treatment group. In the latter 4 groups, the rats were treated with daily gavage of Xixian Pills or TGT 2 weeks after CIA modeling for 3 consecutive weeks. The differentially expressed proteins in high-dose Xixian Pills group and the model group compared with the normal control group were screened based on the tandem mass spectrometry tag (TMT) technology, and the core targets and signaling pathways were analyzed. The immune cell infiltration and gene expression data were analyzed using ggplot2 and tidyverse packages, and the correlation coefficients between the core targets and the immune cells were calculated. RESULTS: The CIA rats showed significantly increased serum levels of TNF-α and IL-6 and lowered serum IL-10 level. Treatments with high- and medium-dose Xixian Pills and TGT all significantly reduced serum TNF‑α and IL-6 and increased IL-10 levels in CIA rats. Proteomic analysis identified 160 differential proteins between the model group and high-dose Xixian Pills group, and the core targets included CCL5, STAT1, GZMB and IL7R. The areas under the ROC curve of CCL5 and STAT1 were both greater than 0.9. Immunohistochemical and immunofluorescence staining revealed increased levels of CCL5 and STAT1 in the ankle joints of CIA rats, which were significantly decreased after treatment with Xixian Pills. CONCLUSIONS Treatment with Xixian Pills offers protection of the joints in CIA rats possibly by inhibiting joint inflammation via regulating protein expressions of CCL5 and STAT1.
Animals ; Drugs, Chinese Herbal/pharmacology* ; Rats ; Arthritis, Rheumatoid/metabolism* ; Proteomics ; Tripterygium/chemistry* ; Arthritis, Experimental/metabolism* ; Tumor Necrosis Factor-alpha/blood* ; Interleukin-10/blood* ; Interleukin-6/blood* ; Male ; Rats, Sprague-Dawley ; Signal Transduction

OBJECTIVE: Rheumatoid arthritis (RA) is a systemic autoimmune disease that affects the small joints of the whole body and degrades the patients' quality of life. Zhengqing Fengtongning (ZF) is a traditional Chinese medicine preparation used to treat RA. ZF may cause liver injury. In this study, we aimed to develop a prediction model for abnormal liver function caused by ZF. METHODS: This retrospective study collected data from multiple centers from January 2018 to April 2023. Abnormal liver function was set as the target variable according to the alanine transaminase (ALT) level. Features were screened through univariate analysis and sequential forward selection for modeling. Ten machine learning and deep learning models were compared to find the model that most effectively predicted liver function from the available data. RESULTS: This study included 1,913 eligible patients. The LightGBM model exhibited the best performance (accuracy = 0.96) out of the 10 learning models. The predictive metrics of the LightGBM model were as follows: precision = 0.99, recall rate = 0.97, F1_score = 0.98, area under the curve (AUC) = 0.98, sensitivity = 0.97 and specificity = 0.85 for predicting ALT < 40 U/L; precision = 0.60, recall rate = 0.83, F1_score = 0.70, AUC = 0.98, sensitivity = 0.83 and specificity = 0.97 for predicting 40 ≤ ALT < 80 U/L; and precision = 0.83, recall rate = 0.63, F1_score = 0.71, AUC = 0.97, sensitivity = 0.63 and specificity = 1.00 for predicting ALT ≥ 80 U/L. ZF-induced abnormal liver function was found to be associated with high total cholesterol and triglyceride levels, the combination of TNF-α inhibitors, JAK inhibitors, methotrexate + nonsteroidal anti-inflammatory drugs, leflunomide, smoking, older age, and females in middle-age (45-65 years old). CONCLUSION This study developed a model for predicting ZF-induced abnormal liver function, which may help improve the safety of integrated administration of ZF and Western medicine. Please cite this article as: Yu Z, Kou F, Gao Y, Lyu CM, Gao F, Wei H. A machine learning model for predicting abnormal liver function induced by a Chinese herbal medicine preparation (Zhengqing Fengtongning) in patients with rheumatoid arthritis based on real-world study. J Integr Med. 2025; 23(1): 25-35.
Humans ; Arthritis, Rheumatoid/drug therapy* ; Drugs, Chinese Herbal/therapeutic use* ; Female ; Middle Aged ; Male ; Retrospective Studies ; Machine Learning ; Adult ; Aged ; Liver/physiopathology* ; Alanine Transaminase/blood*

OBJECTIVE: To detect the serum level of chemokine CXC motif chemokine 10 (CXCL-10) and Krebs von den lungen-6 (KL-6) in patients with rheumatoid arthritis associated interstitial lung disease (RA-ILD), and to analyze their correlation with RA-ILD, as well as the significance in RA-ILD. METHODS: A total of 169 RA patients were enrolled in the study. According to imaging findings of with and without ILD in high-resolution computed tomography scans of chest, the subjects were divided into RA-ILD group and RA-non-ILD group. According to the inclusion and exclusion criteria, 80 patients in each of the two groups were finally selected. Two groups were matched according to the 1 ∶ 1 ratio using propensity score matching (PSM). The serum CXCL-10 and KL-6 levels were detected by enzyme-linked immunosorbent assay. The clinical features, laboratory data and medications between the two groups were compared after PSM and the correlation between serum levels and clinical parameters were analyzed. Binary Logistic regression was used to analyze the risk factors of ILD in the RA patients, and the predictive value of CXCL-10 and KL-6 in RA-ILD was evaluated. RESULTS: In this study, 49 patients with RA-ILD and 49 patients with RA-non-ILD were selected by PSM. The levels of CXCL-10 and KL-6 in the RA-ILD group [64.36 (34.01, 110.18) ng/L, 360.70 (236.35, 715.05) U/mL] were significantly higher than those in the RA-non-ILD group [29.80 (16.89, 40.55) ng/L, 210.69 (159.98, 255.50) U/mL] (all P < 0.001). The results of correlation analysis showed that the level of serum CXCL-10 was positively correlated with the Warrick score on chest CT (r=0.378, P=0.007) and negatively correlated with the percentage of forced vital capacity to the predicted value (FVC%, r=-0.338, P=0.018). And the level of KL-6 was positively correlated with rheumatoid factor (RF, r=0.296, P=0.039) and negatively correlated with FVC% (r=-0.436, P=0.002) and the percentage of diffusion capacity for carbon monoxide to the predicted value (DLCO%, r=-0.426, P=0.002). Both univariate and multivariate Logistic regression analysis showed that CXCL-10 and KL-6 were positively correlated with ILD, the values of OR were 1.035 and 1.023 in CXCL-10 and those were 1.004 and 1.005 in KL-6 respectively (P < 0.05). The ROC curves were plotted with CXCL-10 and KL-6. The area under the curve (AUC) was 0.770 and 0.752 respectively. The AUC of combined detection increased to 0.800. CONCLUSION Serum levels of CXCL-10 and KL-6 are significantly elevated in patients with RA-ILD and correlated with the severity of ILD. The combined estimate of them helps to improve the effectiveness of diagnosis.
Humans ; Lung Diseases, Interstitial/etiology* ; Arthritis, Rheumatoid/complications* ; Chemokine CXCL10/blood* ; Mucin-1/blood* ; Female ; Male ; Tomography, X-Ray Computed ; Risk Factors ; Middle Aged

OBJECTIVE: To investigate the clinical and immunological characteristics of anti-synthetase syndrome (ASS) patients overlap with rheumatoid arthritis (RA). METHODS: A retrospective analysis was conducted on ASS patients with arthritis who were treated at Peking University People' s Hospital. Data collected included demographic information, clinical manifestations, laboratory features, lymphocyte subsets in peripheral blood, and treatments. The patients with ASS were divided into two groups based on the presence or absence of RA for comparative analysis. RESULTS: A total of 104 ASS patients with arthritis were included, among whom 23.1% (24/104) were diagnosed with RA. The ASS with RA group had a significantly higher incidence of rapidly progressive interstitial lung disease (RP-ILD) (41.7% vs. 17.6%, P=0.032), number of tender joints [10 (7, 14) vs. 4 (0, 8), P < 0.001], number of swollen joints [4 (2, 8) vs. 2 (0, 4), P=0.012], and rate of bone erosion (47.8% vs. 2.5%, P < 0.001) compared with the non-RA group. Levels of platelets [(289.57±68.74)×10³/μL vs. (247.94±77.04)×10³/μL, P=0.022], erythrocyte sedimentation rate (ESR) [43 (19, 59) mm/h vs. 18 (10, 44) mm/h, P=0.019], and C-reactive protein (CRP) [19.20 (4.80, 55.36) mg/L vs. 5.68 (1.10, 14.96) mg/L, P=0.006] were found significantly higher in the ASS with RA group than those in non-RA group. Analysis of immune cells in peripheral blood mononuclear cell (PBMC) showed that significantly decreased proportions of CLA⁺ Treg cells [(11.12±4.10)% vs. (17.22±8.49)%, P=0.003], B cells [8.56% (4.80%, 11.90%) vs. 14.55% (8.75%, 20.29%), P=0.025], and natural killer (NK) cells [7.56% (4.65%, 13.20%) vs. 13.25% (7.46%, 19.25%), P=0.045] in the overlap group compared with non-RA group. Proportion of Naïve Th cells [(52.66±17.66)% vs. (40.76±14.96)%, P=0.033)] was significantly increased in overlap group compared with non-RA group. Overlap group had lower rate of complete clinical response than non-RA group (16.7% vs. 43.8%, P=0.031). CONCLUSION Among ASS patients with arthritis, those with RA have more severe lung and joint involvement and a lower treatment response rate, highlighting the need for early recognition and aggressive intervention.
Humans ; Arthritis, Rheumatoid/immunology* ; Retrospective Studies ; Lung Diseases, Interstitial/immunology* ; Male ; Myositis/blood* ; Female ; Middle Aged ; Autoantibodies/blood*

OBJECTIVE: To investigate the current status of methotrexate (MTX) application in rheumatoid arthritis (RA) patients. METHODS: The clinical and laboratory data of RA patients who attended in the Department of Rheumatology and Immunology of Peking University Third Hospital from January 1, 2022 to November 31, 2023 were collected retrospectively. In order to figure out the relationship between MTX use and RA disease control, we recorded information including the starting dose, maximum dose, current dose, reasons of discontinuation of MTX, etc. The t test, Mann-Whitney U test, Chi-square test, Fisher' s exact probability and multivariable Logistic regression were used for analysis. RESULTS: A total of 239 RA patients were enrolled, including 201 females and 38 males with a mean age of (54.5±14.3) years. Among them, 101 patients reached the therapeutic target [clinical remission or low disease activity assessed by 28-joint disease activity score (DAS28)-erythrocyte sedimentation rate (ESR)], accounting for 42.2% of the RA patients. Twenty-six patients met the European League Against Rheumatism (EULAR) definition of difficult-to-treat (D2T) RA, accounting for 10.9% of RA patients. The proportion of the RA patients who had ever used MTX was 84. 1%, and those who were currently on it accounted for only 39.7%. The MTX dose was generally low, with a starting dose of (9.5±3.0) mg/week, the maximum dose of 15.0 (10.0, 15.0) mg/week, and the current dose being (12.4±2.7) mg/week. The most common reasons for MTX dose reduction or discontinuation were adverse reactions, mainly including abnormalities of hepatic function, gastrointestinal discomfort, leucopenia, etc. Those who were currently on MTX had a higher rate of treatment to target (52.6% vs. 35.4%, P>0.05), lower disease activity score (DAS28-ESR, 3.6±1.8 vs. 4.2±1.8, P < 0.05), and fewer tender joint counts (4.8±8.3 vs. 8.6±10.4, P < 0.05) as compared with those who were not taking the drug, while swollen joint count, pain visual analog score and patient' s global score, C-reactive protein (CRP) level and ESR level were not significantly different between the two groups. Compared with those who did not reach the target of treatment, those who did had a higher rate of current MTX application (48.5% vs. 33.3%, P < 0.05), but the history of MTX did not differ between the two groups (84.2% vs. 84.1%, P>0.05). The maximum dose of MTX (median 15.0 mg/week vs. 13.7 mg/week, P>0.05) and the current dose [(12.9±2.5) mg/week vs. (11.8±2.8) mg/week, P>0.05] was higher in those who achieved the target, while the starting dose [(9.6±2.8) mg/week vs. (9.5±3.1) mg/week, P>0.05] and the rate of prior MTX (84.2% vs. 83.3%, P>0.05) was comparable between the two groups. The D2T RA patients had a higher rate of previous MTX use (96.2% vs. 82.6%, P < 0.05) and a higher starting dose [(11.6±4.3) mg/week vs. (9.8±2.7) mg/week, P>0.05], while the maximum dose (median 12.5 mg/week vs. 15.0 mg/week, P>0.05) and the current dose were both lower [(11.6±3.2) mg/week vs. (12.5±2.6) mg/week, P>0.05] than the non-D2T RA patients. CONCLUSION The proportion of regular use of MTX among RA patients was low and the dose was generally small. The RA patients with regular use of MTX had a higher rate of achieving treatment target and lower disease activity. Those who achieved the target had a higher rate of current MTX use, higher maximum and current doses than those who did not. The D2T RA patients had lower maximum and current doses of MTX than the non-D2T RA patients. Therefore, increasing the usage and dosage of MTX in RA patients may help to improve the rate of achieving treatment targets.
Humans ; Arthritis, Rheumatoid/drug therapy* ; Methotrexate/therapeutic use* ; Male ; Female ; Middle Aged ; Retrospective Studies ; Antirheumatic Agents/therapeutic use* ; Aged ; Adult ; Blood Sedimentation ; Severity of Illness Index ; Remission Induction

OBJECTIVE: To explore the characteristics and clinical phenotypes of rheumatoid arthritis (RA) and provide the basis for further understanding, interventions and outcomes of this disease. METHODS: RA patients attended at Peking University People's Hospital from 2018 to 2021 were enrolled in the study. Data collection included demographic data, the sites and numbers of joints involved, extra-articular manifestations (EAM), comorbidities and laboratory variables. Statistical and bioinformatical analysis was performed to establish clinical subtypes by clustering analysis based on the type of joint involved, EAM involvement and other autoimmune diseases overlapped. The characteristics of each subtype were analyzed. RESULTS: A total of 411 patients with RA were enrolled. The mean age was (48.84±15.17) years, and 346 (84.2%) were females. The patients were classified into 4 subtypes: small joint subtype (74, 18.0%), total joint subtype (154, 37.5%), systemic subtype (100, 24.3%), and overlapping subtype (83, 20.2%). The small joint subtype had no medium or large joint involvement, and 35.1% had systemic involvement. The erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) levels and platelet count (PLT) were lower than those in other subtypes, and the rates of positive rheumatoid factors (RF-IgA and RF-IgG) were significantly higher in the small joint subtype. The total joint subtype had both large and small joint involvement but no systemic involvement. The rate of morning stiffness and positive antinuclear antibodies (ANA) in this subtype were lower than those in other subtypes. In the systemic subtype, interstitial lung disease and secondary Sjögren syndrome were the most common systemic involvements, with prominent levels of disease activity score 28-joint count (DAS28-ESR and DAS28-CRP). The overlapping subtype was commonly combined with Hashimoto's thyroiditis or primary Sjögren syndrome. Female in the overlapping subtype was more common than in other subtypes. This subtype was characterized by hyperglobulinemia, hypocomplementemia and high rate of positive ANA, especially spotting type. CONCLUSION Based on the clinical features, RA patients could be classified into 4 subtypes: small joint subtype, total joint subtype, systemic subtype, and overlapping subtype. Each subtype had its own clinical characteristics. They help for further understanding and a more individualized treatment strategy of RA.
Female ; Male ; Humans ; Cross-Sectional Studies ; Sjogren's Syndrome ; Rheumatoid Factor ; Arthritis, Rheumatoid ; Blood Sedimentation ; Phenotype